Plasticized uv/eb cured coatings

ABSTRACT

A plasticized ultraviolet or electron beam (UV/EB) cationically cured coating, such as a release layer or print from UV/EB cured inks, comprises polymers with a reactive plasticizer incorporated therein. The cured coating contains the plasticizing additives permanently attached to the polymer matrix, locking them in place, and permanently flexibilizing the cured coating. The cured coating finds use on varied substrates including printable substrates used in conventional printers and those with release layers for adhesive labels. Coating formulations which form these cationically cured coatings comprise cationically polymerizable monomers and/or oligomers, a reactive plasticizer which is food grade, cosmetic grade, medical grade or biologically benign when incorporated in the polymer backbone, and a catalyst.

FIELD OF THE INVENTION

This invention relates to plasticized ultraviolet or electron beam(UV/EB) cured cationic coatings including release layers and print fromUV/EB cured inks, substrates which contain such coatings andcompositions which form these coatings.

BACKGROUND

In the manufacture of UV/EB cured coatings, there are many circumstancesin which it is desirable to soften or plasticize the resulting coatingto improve its resistance to delamination from a flexible surface. Thisis particularly true of UV/EB cured printing inks, where delaminationcan diminish the image quality and UV/EB cured silicone release layers,where lost portions from delamination can clog printer mechanisms,interfering with subsequent printing operations, or more importantly,can result in poor or no release from pressure sensitive adhesives.

Release layers, including silicone release layers, have long been usedto protect the adhesive layers for tapes, labels, wall coverings, andother tacky substances. Cationic silicone release layers are commonlyprepared from UV or EB curable compositions which can contain epoxy orvinyl ether functional siloxanes, including monomers, oligomers and/orpolymers, and cationic photoinitiators that respond to UV light and/oran electron beam (EB). Discussions of epoxy functional siloxanes andcationic photoinitiators used to prepare silicone release layers are setforth in U.S. Pat. Nos. 4,279,717; 5,583,185; 5,500,300; 5,614,640; and5,814,679; which are incorporated herein by reference for the disclosureof epoxy functional siloxanes cationic photoinitiators therein and theuse thereof.

Ultraviolet light cured inks have found use in various printingprocesses. Most comprise a reactive monomer and/or oligomer, aphotoinitiator, one or more a pigments and optional additives. Examplesof cationically initiated ultraviolet light curable inks are describedin U.S. Pat. Nos. 5,391,685, and 5,889,084, which are incorporatedherein by reference for the ink formulations disclosed therein and usethereof.

Of the various types of UV/EB curable inks which are known, many finduse in screen printing, overprint varnishes, flexographic printing andink jet printing methods, examples being those described in U.S. Pat.No. 5,200,438, discussed above, as well as U.S. Pat. Nos. 5,391,685,4,680,368 and 5,500,040.

Cationic photoinitiators generate strong acids on exposure to UV lightor an electron beam (EB). The acids will initiate a chain reaction orpolymerization of epoxy (oxirane), oxetane or vinyl ether functionalgroups.

UV/EB cured coatings, including release layers and print from UV/EBcured inks, can be very brittle, making them very susceptible tomechanical damage. Damage to release layers and print can occur duringprocessing and handling. For example, damage to a release layer canoccur in the slitting process in the manufacture of labels. This damageis believed to contribute to the buildup of the release layer and/oradhesive on printer print heads when thermal printable sheets withintegral labels are used. In another example, damage to print (cracking)from UV/EB cured inks can occur during handling of the printed material.

The use of common inert plasticizers, such as adipic acid esters,phthalic acid esters, ricinoleate acid esters, citrates, epoxides,glycerols, glycols, hydrocarbons, chlorinated hydrocarbons, phosphatesand the like, to make cationic silicone release layers or print fromUV/EB cured inks less brittle can present problems. The inertplasticizers remain mobile in the release layer and print, which makesthem subject to loss over time through migration or extraction.Migration or extraction of the plasticizer from the print can diminishthe appearance of the printed image. Migration or extraction of theplasticizer from the release layers, including silicone release layers,will lead to embrittlement as they age and can lead to changes in theadhesive performance. This can range from increasing the adhesion of theadhesive to the point where a label will no longer release from therelease layer, or deadening adhesion to the point where a label will nolonger stick to the target substrate.

It is desirable to provide plasticized UV/EB cured cationic coatings,including release layers and print from UV/EB cured inks, which do notembrittle over time and are stable.

SUMMARY OF THE INVENTION

The present invention provides stable plasticized UV/EB cationicallycured coatings including release layers and print from UV/EB cured inks.Also provided are substrates that contain these cured coatings andcoating formulations that can form these coatings. These cationicallycured coatings contain plasticizing additives which are permanentlyattached to the polymerized matrix, locking them in place, andpermanently flexibilizing the cured coating. These plasticizingadditives are unable to migrate out of the UV/EB cationically curedcoatings. In addition to maintaining flexibility, the image/printquality from UV/EB cured inks will not be hampered by migratingplasticizers. Furthermore, the adhesion (tack) of any adhesive held inintimate contact with UV/EB cured release layers will not vary over timedue to migrating plasticizing additives.

The coating compositions that form these coatings are comprised of UV/EBpolymerizable monomers and/or oligomers selected from epoxy monomers andoligomers, oxetane monomers and oligomers, vinyl ether monomers andoligomers and combinations thereof known to undergo cationicpolymerization. Also included are one or more cationic photoinitiatorsand one or more reactive plasticizers. Optional components for the UV/EBcured coating compositions include one or more photosensitizers for thecationic photoinitiator(s) and other additives known in the art, whichimprove or enhance application characteristics of the ink or coating.

Additional components for the UV/EB cured inks include one or morecolorants selected from pigments and dyes. Optional components for theUV/EB cured inks include one or more performance additives such aspigment dispersants and defoamers and one or more propellants (volatilesolvents) where the UV/EB cured ink is to be used in a thermal ink jetprinter.

Optional components for the coating compositions that provide UV/EBcured release layers such as silicone release layers include one or morecolorants selected from pigments and dyes, one or more performanceadditives such as pigment dispersants and defoamers.

Conventional epoxy monomers, oligomers and/or polymers, which a) have atleast one oxirane moiety, b) can undergo cationic polymerization and c)have a viscosity suitable for use in conventional coating or printingprocesses, are preferred. The viscosity of the epoxy monomers, oligomersand/or polymers is preferably below about 25,000 cps at 25° C., in theabsence of solvent, for use in such processes, more preferably belowabout 10,000 cps at 25° C., and most preferably below about 1,000 cps at25° C.

Conventional oxetane monomers, oligomers and polymers, which a) have atleast one oxetane group

a 4-membered cyclic ether, comprised of one oxygen atom and 3 carbonatoms, which may have one or more non-hydrogen substituents R, R₁, R₂and R₃ attached to the carbon atoms, wherein R, R₁, R₂ and R₃ arepreferably H or C₁₋₈ alkyl with at least one of R₁ and R₂ being anon-hydrogen substituent, such as —CH₂OH or —CH₂CH₃OH, b) have aviscosity suitable for use in conventional coating or printing processesand c) can undergo cationic polymerization, are suitable. The viscosityof the oxetane monomers, oligomers and/or polymers is preferably below25,000 cps at 25° C., in the absence of solvent, for use in suchprocesses, more preferably below about 10,000 cps at 25° C., and mostpreferably below about 1,000 cps at 25° C. Suitable oxetane monomers canbe prepared by well-known methods such as by the reaction of potassiumhydroxide with 3-chloropropyl acetate at 150 C described by C. R. Nollerin “Trimethylene Oxide”, Org. Synth. 29: 92; Coll. Vol. 3: 835(1955).Suitable hydroxyalkyl oxetane monomers are described by SubhankarChatterjee in EP 1165708, entitled, “Radiation curable water basedcationic inks and coatings.”

Conventional vinyl ether monomers, oligomers and polymers, which a) haveat least one vinyl ether group

wherein R and R′ are each, independently, H or C₁₋₈-alkyl, mostpreferably where both are H (a nonhydrogen R′ is preferred to be CH₃),b) have a viscosity suitable for use in conventional coating or printingprocesses and c) can undergo cationic polymerization, are suitable. Theviscosity of the vinyl ether monomers, oligomers and/or polymers ispreferably below 25,000 cps at 25° C., in the absence of solvent, foruse in such processes, more preferably below about 10,000 cps at 25° C.,and most preferably below about 1,000 cps at 25° C.

Epoxy, oxetane and vinyl ether monomers and oligomers with two or morereactive groups can be used to increase crosslinking. Mixtures of epoxy,oxetane and vinyl ether monomers and oligomers may also be used, as wellas monomers and oligomers containing mixtures of one or more of eachtype of functional group.

For UV/EB cationically curable release layers, suitable epoxy-functionalmonomers, oligomers and/or polymers are organohydrogensiloxanes orpreferably diorganopolysiloxanes (most preferably dimethylsiloxanes),preferably having up to about 20%, more preferably having up to about15%, and most preferably, having up to about 10% by weight aliphaticepoxide, cycloaliphatic epoxide or glycidyl ether groups, typically offrom 2 to 20 carbon atoms, most preferably cycloaliphatic epoxidegroups. These epoxy-functional siloxanes can be produced by a preciousmetal catalyzed hydrosilation reaction between a SiH-functional silaneor siloxane and an olefin epoxide which contains both ethylenicunsaturation and epoxide functionality. Suitable hydrosilation reactionsbetween olefin epoxides and organohydrogensiloxanes ordiorganopolysiloxanes are described by Eckberg in U.S. Pat. Nos.4,279,717 and 5,258,480. Examples of suitable olefin epoxides include4-vinylcyclohexeneoxide, vinylnorbornene monoxide,dicyclopentadienemonoxide, allyl glycidyl ether and glycidyl acrylate.Alternately, suitable epoxy-functional poly diorganopolysiloxanes can besynthesized by condensation reactions between, for example, hydroxyl oralkoxy terminated silicone fluids and epoxy-functional alkoxy silanes ofthe type typically referred to as coupling agents. The epoxy-functionalsilicones obtained which have a viscosity of from about 50 centipoise toabout 25,000 centipoise at 25° C. are suitable.

Commercially available epoxy-functional linear polydimethylsiloxanepolymers developed for photocurable release coating applications are theSILCOLEASE® UV200 series available from Bluestar Silicones® of NewBrunswick N.J., for example, UV POLY 200, UV POLY 205, UV POLY 206, UVPOLY 215, and UV POLY 230.

Other commercially available epoxy-functional linearpolydimethylsiloxane polymers developed for photocurable release coatingapplications include the SILFORCE® UV9300, SILFORCE® UV9315, SILFORCE®UV9400, and SILFORCE® UV9430 polymers available from MOMENTIVE® ofColumbus Ohio. The SILFORCE® polymers can be blended with a conventionalcationic photocatalyst, applied to substrates using standard coatingtechniques and rapidly crosslinked on exposure to ultraviolet light.

Other commercial sources of suitable epoxy functionalpolydimethylsiloxane monomers, oligomers and polymers are available fromsuppliers such as Cytek Industries, Evonik (Degusa), Gelest,Monomer-Polymer and Dajak Laboratories, among others.

For UV/EB cationically curable inks, suitable monomers, oligomers and/orpolymers are generally comprised of structures in which atomic siliconis only present at a low molar percent or are completely free of atomicsilicon, and have a reactive group functional equivalency of from 1 toabout 6 or more, preferably 1 to about 3, such reactive functionalitycomprised of cycloaliphatic epoxy groups and/or oxetane groups (asdefined above) and/or vinyl ether groups (as defined above).

Examples of preferred epoxies for UV/EB cationically curable inksinclude:

(1) monofunctional monomers/oligomers which contain cycloaliphatic epoxyreactive groups, cycloaliphatic monoepoxies, such as 4-ethyl-cyclohexeneoxide, 4-propyl cyclohexene oxide, 4-vinylcyclohexene oxide (VCHO), andmixtures of cycloaliphatic monoepoxies available from Union Carbideunder the trade name UVR 6100 having an epoxy equivalent weight of 130to 140, 1-methyl-4-isopropenyl cyclohexene oxide (limonene oxide),dicyclopentadiene monoxide, 7-vinylnorborene monoxide, silicone epoxyoligomers, alpha pinene oxide, trimethylolpropane oxetane, alkyl vinylethers, cycloaliphatic vinyl ethers, aryl vinyl ethers and the like;

(2) bifunctional monomers such as limonene dioxide, cycloaliphaticdiepoxides such as bis(3,4-epoxycyclohexyl)adipate and3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate (commerciallyavailable from Dow under the trade name Cyracure® 6110 and from Sartomerunder the trade name Sarcat®), dicyclopentadiene dioxide, ethyleneglycol divinyl ether, butanediol divinyl ether, cyclohexanediol divinylether and the like; and

(3) polyfunctional monomers, which contain more than 2 cationic reactivegroups and the like.

Specific examples of suitable monomers and oligomers for UV/EBcationically curable inks include vinylcyclohexene oxide,vinylcyclohexene dioxide, cyclohexene oxide,3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate,3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate,bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, dicyclopentadienedioxide, trimethylolpropane oxetane, ethylene glycol divinyl ether,butanediol divinyl ether and cyclohexanediol divinyl ether.

Examples of suitable commercially available UV/EB cationically curableepoxy monomers are UVACURE® 1550 resin (cycloaliphatic diepoxide),UVACURE® 1530 resin (hydroxy modified-cycloaliphatic diepoxide),UVACURE® 1533 resin (acrylic modified-cycloaliphatic diepoxide) andUVACURE® 1534 resin (hydroxy modified-cycloaliphatic di-epoxide),available from Cytec Industries Inc., Woodland Park, N.J.

For UV/EB cationically curable silicone release layers, suitable vinylether functional siloxane monomers, oligomers and/or polymers are of theformula:

(CHR═CR′—O—Z)_(n)-A,

wherein A is a polysiloxane with from up to about 150 silicon atoms; nis an integer of 1 to about 10, Z is a direct bond or a divalent moietyhaving C₁₋₂₀ carbon atoms selected from the group consisting ofalkylene, cycloalkylene, or polyalkylene ether moieties and R and R′ areeach, independently, H or C₁₋₈ alkyl. Examples of photopolymerizableorganopolysiloxanes having a vinyl ether groups are described in U.S.Pat. No. 4,617,238 to Crivello, U.S. Pat. No. 4,707,503 to Itoh et al.,U.S. Pat. No. 5,057,549 to Herzig et al., European Patent PublicationNo. 0462389, U.S. Pat. No. 5,039,716 to Vara et al., and U.S. Pat. No.5,861,467 to Bujanowski et al.

For UV/EB cationically curable inks, suitable monomers, oligomers and/orpolymers having at least one or more vinyl ether groups include thosedisclosed in U.S. Pat. No. 4,950,696 and those of the following generalformula:

(CHR═CR′—O—Z)_(n)—B,

wherein R, R′, Z and n are as defined above and B is hydrogen or amoiety derived from mono-, di-, tri- or tetrafunctional aliphatichydrocarbons, cycloaliphatic hydrocarbons, aromatic hydrocarbons,alcohols, esters, ethers, siloxanes, and carbonates, of from 1 to about40 carbon atoms. In addition to inks, EP 0656016 B1 to Crivello et al.also discloses silicone-free release coatings obtained from UVcationically curable vinyl ethers.

Suitable vinyl ether functional aliphatic monomers can also be definedby the following formulae:

(CHR═CR′—O—(Z—O)_(m))_(n)—B₂,

wherein R, R′ and n are as defined above, m is an integer of from 0 toabout 5, Z is a divalent moiety having C₁₋₂₀ carbon atoms selected fromthe group consisting of alkylene, cycloalkylene, or polyalkylene ethermoieties, and B₂ is hydrogen or a moiety derived from mono-, di-, tri-or tetra-functional aliphatic hydrocarbons or cycloaliphatichydrocarbons.

Preferred mono- and difunctional aliphatic vinyl ether monomers includethose based on normal alkanes, which have the general formula:

CHR═CR′—O—(CH₂)_(y)—B₃,

wherein R and R′ are as defined above, y is an integer of from 1 toabout 18, and B₃ is hydrogen, —OH, or —O—CR′═CHR.

Preferred mono- and difunctional aliphatic vinyl ether monomers alsoinclude those based on ethylene glycols, which have the general formula:

CHR═CR′—(OCH₂CH₂)_(y′)—B₃,

wherein R, R′ and B₃ are as defined above and y′ is an integer of from 1to about 6.

Other preferred mono- and difunctional aliphatic vinyl ether monomersinclude those based on 1,2-propanediol (propylene glycol), which havethe general formula:

CHR═CR′—(OCH(CH₃)CH₂)_(y′)—B₃

or

CHR═CR′—(OCH₂CH(CH₃))_(y′)—B₃,

wherein R, R′, B₃ and y′ are as defined above and x is an integer whichis 3 or 4.

Additional preferred mono- and difunctional aliphatic vinyl ethermonomers include those based on 1,3-propanediol, 1,4-butanediol and1,6-hexanediol, which have the general formula:

CHR═CR′—(O(CH₂)_(x))_(y′)—B₃,

wherein R, R′, B₃ and y′ are as defined above and x is an integer whichis 3, 4 or 6.

Suitable vinyl ether functional monomers include those based on esters,which have the general formula:

(CHR═CR′—O—Z—O—C(O))_(n)—B₄,

wherein R, R′, Z and n are as defined above and B₄ is a mono-, di-,tri-, or tetrafunctional moiety having from 1 to about 16 carbon atomsselected from the group consisting of alkylene, cycloalkylene, aryleneand aralkylene moieties.

Suitable vinyl ether terminated monomers include those based on ethermonomers, which have the general formula:

CHR═CR′—O—[CH₂CH₂O]_(m)—B₅,

wherein R and R′ are as defined above, m is an integer of 2 to about 5and B₅ is hydrogen, or —CR′═CHR.

Suitable vinyl ether terminated aromatic monomers include those whichhave the general formula:

(CHR═CR′—O—Z—O)_(n)—B₆,

wherein R, R′, Z and n as defined above, and B₆ is a mono-, di-, tri- ortetra-functional aromatic moiety having 6 to about 40 carbon atoms.

Suitable vinyl ether terminated carbonate monomers include those whichhave the general formula:

(CHR═CR′—O—Z—O)_(n)—(O—C(O)—O)_(p)—B₇,

wherein R, R′, Z and n as defined above, p is an integer of from 0 to 3and B₇ is a diester, diol or polyol moiety of from 2 to about 20 carbonatoms.

Specific vinyl ethers which are suitable for UV/EB cationically curableinks include ethyl vinyl ether, propyl vinyl ether, isobutyl vinylether, octadecyl vinyl ether, hydroxybutyl vinyl ether,4-(hydroxymethyl)cyclohexyl methyl vinyl ether, 2-methoxy ethyl vinylether, propenyl ether of propylene carbonate, dodecyl vinyl ether,cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, n-butyl vinyl ether,tert-butyl vinyl ether, ethyleneglycol monovinyl ether, diethyleneglycoldivinyl ether, butanediol monovinyl ether, butane diol divinyl ether,hexane diol divinyl ether, ethylene glycol butyl vinyl ether,triethyleneglycol divinyl ether, triethylene glycol methyl vinyl ether,cyclohexane dimethanol monovinyl ether, cyclohexane dimethanol divinylether, 2-ethylhexyl vinyl ether, poly-THF divinyl ether,CHR═CR—[O(CH₂)₄—O]_(n)—CR═CHR, pluriol-E-200-vinyl ether,CHR═CR—[OCH₂CH₂]_(n)—O—CR═CRH, and the like.

The plasticizing additives are selected from a class of plasticizerswhich possess one or more functional groups that can react as chaintransfer groups or chain terminating groups for a cationicallypropagating chain end, i.e., preferably —OH (alcohol) or —COOH(carboxylic acid) groups, epoxy groups, oxetane groups, or vinyl ethergroups positioned along the polymer backbone, preferably as branches orside chains, or at the chain ends of branched polymers, where thebranches do not contain reactive groups so as to increase the freevolume between polymer molecules, whether a silicone polymer backbone inthe case of a silicone release layer or a nonsilicone backbone in thecase of UV/EB cationically curable inks. Multiple functional groups arepreferred to ensure the plasticizer is integrated into the polymermatrix during the rapid polymerization reaction and preferably attach tomore than one polymer chain. Plasticizers bound this way will not “bleedout” or “bloom” because of their permanent chemical integration into thepolymer matrix.

Preferably, the plasticizing additives are selected from natural orsynthetic biologically benign (harmless if ingested: preferably food,medical or cosmetic grade) materials, which more preferably arematerials generally recognized as safe (GRAS) by the FDA for inclusionin foods (direct contact), FDA approved as constituents in coatings andadhesives used in direct and indirect food contact, medical or cosmeticgrade materials. Where the reactive plasticizer is highly reactive andcompletely incorporates fully into the polymer backbone, it isconsidered biologically benign in that state.

Examples of suitable reactive plasticizing additives include a) fattyacids, b) mono-, di- and triglycerides, which contain reactive alcoholgroups, c) diols or polyols, d) diacids and their monoesters, e) lowmolecular weight polyesters (linear or branched) having one or morealcohol groups or one or more carboxylic acid groups present as sidechains or end groups, and f) polyacrylate copolymers containingcomonomers with free —OH and/or —COOH groups, such as hydroxy(m)ethylacrylate, (meth)acrylic acid or maleic anhydride, etc. The reaction ofthe alcohol groups with the propagating cationic intermediates willtypically form ether linkages and reaction of the carboxylic acid groupswith the propagating cationic intermediates will typically form esterlinkages.

Fatty acids and triglycerides derived from the following oils have beenapproved for use by the FDA as indirect food additives in polymericcoatings (See 21 CFR 175.300): beechnut, candlenut, castor, chinawood(tung), coconut, corn, cottonseed, fish (refined), hempseed, linseed,oiticica, perilla, poppy seed, pumpkin seed, safflower, sesame, soybean,sunflower, walnut and tall oil. Those fatty acids and triglycerides withfree OH and/or COOH groups are suitable for use in this invention.

Also approved are esters of these fatty acids derived from butyleneglycol, ethylene glycol, pentaerythritol, polyethylene glycol,polypropylene glycol, propylene glycol, sorbitol, trimethylol ethane andtrimethylol propane. Esters with free —OH and/or —COOH groups aresuitable for use in this invention.

The following acids have been approved for use by the FDA as indirectfood additives in polymeric coatings (See 21 CFR 175.300) and aresuitable for use in this invention: adipic acid,1,4-cyclohexanedicarboxylic acid, dimerized fatty acids derived from theoils identified above, fumaric acid, maleic acid, isophthalic acid,2,6-naphthalenedicarboxylic acid, orthophthalic acid, sebacic acid,terephthalic acid and trimellitic acid.

The following acids and esters have been categorized by the FDA asGenerally Recognized as Safe (GRAS) as direct food additives and aresuitable for use in this invention: aconitic acid, agamic acid, benzoicacid, caprylic acid, citric acid, lactic acid, linoleic acid, malicacid, propionic acid, stearic acid, succinic acid, tannic acid, tartaricacid, and diacetyl tartaric acid of mono- and diglycerides.

The following alcohols have been approved for use by the FDA as indirectfood additives in polymeric coatings (See 21 CFR 175.300) and aresuitable for use in this invention: butylene glycol, diethylene glycol,ethylene glycol, glycerol, mannitol, [alpha]-methyl glucoside,pentaerythritol, propylene glycol, sorbitol, trimethylol ethane,trimethylol propane, cetyl alcohol, decyl alcohol, lauryl alcohol,myristyl alcohol, octyl alcohol and stearyl alcohol.

The following plasticizers approved for use by the FDA as indirect foodadditives in polymeric coatings (See 21 CFR 175.300) are suitable foruse in this invention: propylene glycol, triethylene glycol, dipropyleneglycol, mannitol, sorbitol, p-tert-butyl phenyl salicylate, epoxidizedsoybean oil, glyceryl monooleate, monoisopropyl citrate, mono-, di-, andtristearyl citrate, triethyl citrate, 3-(2-xenolyl)-1,2-epoxypropane,dihydroxy dichlorodiphenyl methane, glycerol and tributyl citrate.

The following plasticizers have been approved for use by the FDA asindirect food additives in polymeric coatings (See 21 CFR 175.300) butrequire modification to provide a free —OH and/or —COOH group for use inthis invention: acetyl tributyl citrate, acetyl triethyl citrate,butylphthalyl butyl glycolate, butyl stearate, dibutyl sebacate, diethylphthalate, diisobutyl adipate, diisooctyl phthalate, ethyl phthalylethyl glycolate, glycerol triacetate, di-2-ethylhexyl phthalate,triethylene glycol di-caprylic acid, 1,4-benzene dicarboxylic acidbis(2-ethyl hexyl) ester, and 1,2-benzenedicarboxylic acid dinonylester, dibutyl phthalate, cyclohexyl phthalate, diethylene glycoldibenzoate, dipropylene glycol dibenzoate, dibutyl sebacate, diheptyladipate, dioctyl adipate, and dinonyl adipate.

Although not preferred, the reactive plasticizers may have anhydride,amide, imide, urethane, beta-dicarbonyl or thiol groups in addition toor instead of one or more alcohol groups or one or more carboxylic acidgroups. These groups are also reactive with the propagating carboniumion of cationically polymerizable functional groups and can form ester,thioether or N—C linkages with the polymer backbone. With the exceptionof the anhydride group, all materials with Pk_(a)s (acidity constants)less than about 16 can be considered potential reactive plasticizers.

Examples of fatty acids which possess functional groups (preferably twoor more) that can react as chain transfer groups or chain terminatinggroups for a cationically propagating chain end include derivatives ofnatural unsaturated fatty acids such as palmitic, linolenic, oleic,linoleic acids, dimer acids, and tall oil fatty acids with preferablytwo or more functional groups and derivatives of saturated fatty acids,such as myristic acid, stearic acid, capric acid and lauric acid withpreferably two or more functional groups. Examples include fatty acids(saturated or unsaturated) that have been reacted with multifunctionalalcohols such as glycerol, ethylene glycol or propylene glycol to formglycerides and glycols with reactive alcohol groups.

Also suitable are mono-, di- and triglycerides or esters (benzoates,citrates, and phthalates), which contain reactive alcohol groups, formedfrom multifunctional alcohols (glycerol, ethylene glycol or propyleneglycol, triethylene glycol, tetraethylene glycol) and acids such asbenzoic acid, hexanoic acid, heptanoic acid, citric acid, cyclohexanedicarboxylic acid, phthalic acid, isophthalic and terephthalic acid.

Suitable diols include linear and branched aliphatic diols such as, forexample, 2-methyl-1,3-propanediol and 2-methyl-2,4-propanediol; ethyleneglycol; 1,2- and 1,3-propanediol; 1,2-, 1,3-, 1,4- and 2,3-butane-diol;1,2-, 1,3-, 1,4- and 1,5-pentanediol; 1,6-hexanediol; 1,8-octanediol;1,10-decanediol; diethylene glycol, triethylene glycol, tetraethyleneglycol, dipropylene glycol, tripropylene glycol and neopentyl glycol;pentaerythritol; cyclohexanedimethanol; 2,2,4-trimethylpentane-1,3-diol.These can be used alone or in combination with other reactiveplasticizers. Suitable cyclic aliphatic diols include 1,2-, 1,3-,1,4-cyclohexane diols. Suitable aromatic diols include resorcinol andbisphenol-A.

Suitable polyols include glycerol, ethylene glycol, propylene glycol,pentaerythritol and resveratrol.

Suitable diacids and their monoesters include short chain aliphaticdiacids (C₂-C₁₈) such as oxalic, malonic, succinic, glutaric, adipic,pimelic and suberic acid and long chain diacids (C₉-C₁₈) such asnonanedioic (azelaic), decanedioic (sebacic), and dodecanedioic acid.

Suitable diacids and their monoesters also include aromatic diacids suchas phthalic acid, isophthalic acid, terephthalic acid and anhydridessuch as phthalic anhydride and trimellitic anhydride.

Suitable low molecular weight polyesters (linear or branched) having oneor more alcohol groups and/or one or more carboxylic acid groups presentin side chains or as end groups can be prepared from reaction ofdicarboxylic acids (or anhydrides) with diols and or polyols, such asthose described above, and include sebacates, adipates, phthalates,terephthalates, dibenzoates, gluterates, azelates and citric acid.

Phthalate-, trimellitate-, adipate- sebacate- and maleate-basedplasticizers having more than one alcohol group or one or morecarboxylic acid group are also suitable.

Suitable reactive plasticizing molecules have reactive group equivalentweights up to about 600 Daltons, more suitable molecules have reactivegroup equivalent weights up to about 1,200 Daltons, and the mostsuitable molecules have reactive group equivalent weights up to about2,500 Daltons.

Examples of commercially available low molecular weight polyesterplasticizers, typically used in cosmetics (linear or branched) havingone or more alcohol groups or one or more carboxylic acid groups whichare suitable include the PELEMOL® polyesters available from PhoenixChemical Inc. of Somerville, N.J. Specific examples include PELEMOL® P3Dpolyester (polypropanediol dimer dilinoleate, propane diol esterifiedwith fatty acid dimers having an acid number of 35) and PELEMOL® DDpolyester (dimer dilinoleyl dimer dilinoleate with a hydroxyl numberbetween 40-60). Others include PELEMOL® 6G22 (polyglyceryl-6 behenate),PELEMOL® 6GPR (polyglyceryl-6 polyricinoleate), PELMOL® D9336diisopropyl dimer dilinoleate and PELMO® D3GP (dimer dilinoeyl dimerdilinoleate (and) propanediol dicaprylate/caprate (and) polyglyceryl-3behenate).

Besides being biologically benign and containing at least one reactivegroup that enables the plasticizing additive to react into the polymerbackbone, the preferred plasticizing additive must also be soluble inthe coating formulation as applied to the substrate prior to cure andpreferably have a melting point below about 40° C. to facilitateblending into the liquid coating formulation.

To improve compatibility with coating formulations for silicone releaselayers, a silicone based plasticizer can be used. An example of such aplasticizer is SILFORCE® UV9440E polymer by MOMENTIVE® of Columbus OhioSILFORCE® UV9440E is a polydimethyl silicone polymer with diol endgroups having a hydroxyl equivalent weight of about 2,500 Daltons. Suchplasticizers are preferably used with a coupling agent.

Such additives employed to plasticize the cationic inks and coatings areuseful at relatively low levels. Typically, improvements are observed atbetween about 2 and about 15 weight percent on the total weight of theformulation, but will depend on the solubility, functional group density(equivalent weight) and type of functional groups present in thereactive plasticizers.

Suitable optional coupling agents have one functional group thatparticipates in the cationic cure, such as an oxirane, oxetane or vinylether group and one or more functional groups that react with alcoholgroups and/or carboxylic acid groups. These functional groups includealkoxyl groups, acetoxy groups, carboxyl groups, chlorosilane groups andsilane ester groups.

Coupling agents of the type R¹ _(n)—Si—OR² _((4-n)) are particularlysuitable where n is an integer from 1-3, preferably 2 and mostpreferably 1, R′ contains a cationic-reactive group, particularly acycloaliphatic epoxy, vinyl ether, or oxetane moiety, and R² is ahydrocarbon containing up to six carbon atoms, preferably with 4 orfewer carbon atoms, and more preferably with 2 or fewer carbon atoms.

Examples of suitable coupling agents include the epoxy silanes availablefrom GELEST® Inc. of Morrisville, Pa. These include SIE 4666.0 epoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxy silane, SIE 4668.0(2-(3,4-epoxycyclohexyl)ethyltriethoxy silane), SIE 4670.0(2-(3,4-epoxycyclohexyl)ethyltrimethoxy silane), and SIE 4675.0(5,6-epoxyhexyl triethoxy silane).

Such additives employed to enhance the efficiency of the reactiveplasticizers are useful at low levels. Typically, improvements areobserved at between about 0.1 and about 2 weight percent on the totalweight of the formulation, but will depend on the types of functionalgroups present in both the coating or ink formulation and the reactiveplasticizer, the reactive group densities (equivalent weights) for eachtype of functional group present, the type of substrate the coating orink is applied to, and the presence of water on/in the substratesurface, among other variables.

It is contemplated that intermediates to the coating formulationsdescribed above which comprise: a) one or more coupling agents of theformula: R¹ _(n)—Si—OR² _((4-n)) and b) the UV/EB cationicallypolymerizable monomers and/or oligomers described above, have utilitywithout a reactive plasticizer present. Such intermediate coatingformulations will aid the adhesion of the cured coating to the surfaceof a substrate with free oxide, OH and/or COOH groups, such as coatedpapers and anodized metals. The coupling agents integrate into the UV/EBcured polymer during cationic polymerization and also react with theactive groups on the surface of the substrate. Although not wishing tobe bound by theory, it is contemplated that some reaction between thecoupling agent and the surface of the substrate occurs even where thereactive plasticizer is present within the coating formulations andcured coatings of the present invention.

Suitable photoinitiators include those compounds which form aproticacids or Bronsted acids upon exposure to visible and/or UV light or EBradiation sufficient to initiate polymerization. These are distinguishedfrom photoinitiators used to generate free radicals such as aromaticalpha-hydroxy ketone, aromatic phosphine oxide, and benzophenone classesof photoinitiator structures. Most cationic UV photoinitiators absorbphoton energy at a wavelength in the range of 300-450 nm. Thephotoinitiator used may be a single compound, a mixture of two or moreactive compounds or a combination of two or more different compounds,i.e., co-initiators which form part of a multi-component initiatingsystem. The photoinitiator is preferably incorporated in an amount offrom 0.01 to 10 wt. %, based on the total weight of the ink or coatingformulation, most preferably about 2 to about 5 wt. % of the total inkor coating formulation. When the amount of photoinitiator is too low,cure is insufficient and where an excessive amount is used, rapid cureresults in a decrease in cured molecular weight and reduced smearresistance.

Examples of suitable cationic photoinitiators are listed below:

Aryldiazonium salts of the formula: Ar—N₂ ⁺X⁻,Diaryliodonium salts of the formula: Ar₂—I⁺X⁻,Triarylsulphonium salts of the formulae Ar₃—S⁺X⁻, Ar—S—Ar—S⁺(Ar)₂X⁻, orS—(Ar₃—S⁺X⁻)₂,Triaiylselenonium salts of the formula: Ar₃—Se⁺X⁻,Dialkylphenacylsulphonium salts of the formula Ar—C(O)—CH₂—S⁺R₂X⁻,Aryloxydiarylsulphoxonium salts of the formula Ar₃—S⁺(O)X⁻,Dialylphenacylsulphoxonium salts of the formulaAr—C(O)—CH₂(R)—S⁺(O)—RX⁻,wherein Ar is a phenyl or substituted phenyl group (one or more non-Hsubstituents on the phenyl ring) or a naphthyl or substituted naphthylgroup (one or more non-H substituents on the naphthyl rings), R is aC₁₋₁₀ hydrocarbon based moiety and X is a non-nucleophilic counter ion.

The counter ions are typically SbF₆ ⁻, AsF₆ ⁻, PF₆ ⁻ and BF₄ ⁻. Examplesof suitable commercial photoinitiators are given below in Table 1.

TABLE 1 Suppliers of UV and visible light photoinitiators for cationicpolymerizations. Type of Photoinitiator Trade Name SupplierTriarylsulphonium salts GARICURE ® PI Guarson Chem. 6990 Co. Ltd MixedTriarylsulphonium salts GARICURE ® PI Guarson Chem. 6992 Co. LtdTriarylsulphonium salts Degacure KI85 Degussa Triarylsulphonium saltsSP-55 ADEKA Triarylsulphonium salts SP-150 ADEKA Triarylsulphonium saltsSP-170 ADEKA

Additionally, photosensitizers can be incorporated to improve theefficiency with which the photoinitiators use the energy delivered tothe coated substrate, enabling increased line speeds or reduced powerand facilitate proper coating cure. Useful photosensitizers includethioxanthones among other compounds well known and commerciallyavailable from numerous sources. Photosensitizers are typically used atabout 5 to about 25 weight percent on the photoinitiator, but this ruleof thumb can vary widely depending on the particular formulation,specific choice of photosensitizer and photoinitiator, energy transferefficiencies between the photosensitizer and photoinitiator and coatingthickness, to name but a few of the important variables.

It is critical that the ink or release coatings be sufficiently cured soas to limit migration of components (monomers, oligomers, polymers,plasticizers, etc.) therein. It is preferable that the coatings formedhave less than about 4 wt. % extractables, based on the total weight ofthe coating, after exposure to a suitable solvent (acetone, isopropylalcohol, toluene, hexane, etc.).

The photoinitiators are typically responsive to UV light (delivered byhigh pressure mercury lamps, xenon-lamps, arc lamps and gallium lamps ina conventional light array or light box) or electron beam (EB)irradiation.

The coating compositions may contain particulate fillers to enhancestrength. The fillers must be of a size which does not scatter U.V.light and are preferably less than ½ the size at which they scatterlight, so as not to interfere with penetration of the UV radiation andcuring of the coating composition. Underivatized, and in some cases,surface modified fumed silica, is a preferred filler. Fumed silicaparticles are preferably less than 200 nanometers and more preferablyare less than 20 nanometers in diameter. Suitable examples ofparticulate silicas include those available from Cabot Corporation,Cab-o-sil Division, Tuscola, Ill., under the trade name Cab-o-sperse®.

Preferred coating amounts which provide such layers with adequaterelease properties, in the case of release coatings, or color strength,in the case of inks, range from 0.01 to 10 g/m² (solids content) andmore preferably range from 0.10 to 5.0 g/m² (solids content).

The cationic UV curable ink formulations of the present inventioncontain a coloring agent which is capable of being sensed visually, byoptical means, by magnetic means, by electroconductive means or byphotoelectric means. This coloring agent is typically a dye or pigmentincluding a variety of organic and inorganic coloring pigments and dyes.Care needs to be exercised when selecting pigments, dyes, dispersantsand surfactants, etc. for these cationic systems, as any component whichhas basic character—amine/amide/imide groups, salts with nonfugitivecations (sodium, potassium, quaternary ammonium counter ions, etc. forcarboxylic, sulfonic, phosphonic acids, etc.) will poison/neutralize theactive acid catalysts and inhibit or prevent cationic polymerization.

The total amount of coloring agent is typically from about 0.01-10 wt. %of the total ink formulation. Dispersing agents may optionally be usedin the ink formulation to help disperse the pigments. Pigments areinsoluble colorant particles and require dispersants to form stabledispersions. Dyes are soluble colorants, and will molecularly disperseor dissolve in the formulation to form a homogeneous solution.

The coating formulations which provide silicone release layers may alsooptionally have a coloring agent (dye or pigment), if desired.

Care is also necessary in selecting a substrate to ensure basiccomponents are not exposed on the surface to cause inhibition of UVcuring through neutralization of the active photocatalyst. The surfaceof the substrate may be subjected to the conventional surface treatmentssuch as a chromic acid treatment, an ozone exposure, a flame exposure, ahigh pressure electric shock exposure, or an ionizing radiationtreatment, in order to increase adhesion of the silicone release layer.

Where the silicone release layer is used to protect a pressure-sensitiveadhesive, conventional pressure-sensitive adhesives can be used with noparticular limitation. The pressure-sensitive adhesive can be applied tothe face of a substrate opposite to that where the silicone releaselayer is formed as described in U.S. Pat. No. 7,618,685. The pressuresensitive adhesive will then contact the silicone release layer when thesubstrate is rolled onto itself. The pressure-sensitive adhesive layermay be applied to the substrate prior to forming the silicone releaselayer or alternatively, the silicone release layer can be formed priorto application of the pressure-sensitive adhesive layer.

The coating formulations of the present invention adhere well to varioussubstrates such as coated and uncoated paper, wood, plastics, glass,ceramics and metal. The coating formulations of this invention can beapplied to substrates by any conventional coating means, for example, bybrushing, dipping, spray-coating, roller coating, offset, gravure,flexographic, lithography, ink jet, transfer roll coating or applicationwith a reverse roll, dip roll, kiss roll, spray coater, air knife, barcoater or doctor blade, such as a Myer rod.

The viscosity of the coating formulations can be adjusted as necessaryfor the particular coating/printing method preferably by choosingreactive components that provide the desired liquid (for application)and cured (for end use) characteristics. Volatile solvents can be usedto reduce viscosity but are not preferred. For example, ink jet inkstypically have a viscosity in the range of 1-500 cps at 25° C.,preferably 1-100 cps and most preferably between 1-25 cps. Flexographicinks typically have a viscosity in the range of about 35 cps to about200 cps at 25° C. Inks used in gravure printing typically have aviscosity in the range of about of 25 cps to about 200 cps at 25° C.Inks used in lithography typically have a viscosity in the range of fromabout 100 cps to about 1100 cps.

Inks used in thermal ink jet printing typically contain a propellant(solvent), defoaming agents, flow adjusters, leveling agents orcobwebbing preventative agents to improve their properties as jetprinting inks.

The coating formulations are typically cured by exposure to UVradiation, but they can also be cured by exposure to electron beam (EB)radiation. The purpose of the high energy irradiation is to generate theactive acid catalyst from the photoinitiator, which initiates the curereactions. Once the active (acid) catalyst is generated, the curechemistry is subject to the same rules of thermodynamics as any chemicalreaction—the reaction rate is accelerated by heat. Therefore, a “darkcure” can be used after activating the catalysts by exposure to UV/EBirradiation to increase the rate and extent of cure. This isaccomplished by a subsequent heat treatment, such as by passing thesubstrate through an oven. The practice of using thermal treatments toenhance the cationic UV cure of monomers is generally known in the art.Examples of such techniques include those described by Crivello et al.,“Dual Photo- and thermally initiated cationic polymerization of epoxymonomers,” J. Polym. Sci. A Polym. Chem., Vol. 44, Issue: 23, pp.6750-6764, (Dec. 1, 2006).

Exposing these coating formulations to UV light causes a rapidpolymerization. The UV initiated reaction cures the coating formulationto a tack-free, smear-free layer in less than 1 minute directly on thesubstrate. In the preferred embodiments, the polymerization requiresless than 1 second. The rate of the cure reaction depends on the amountof photocatalyst and specific coating resins present in the formulation,the coating thickness, pigmentation, dose rate and length of exposure.In general, however, lower power delivered to the substrate requires alonger exposure to affect cure.

The present invention also provides coated substrates where the coatingis either a UV cured ink, a UV cured silicone release layer or both.Suitable substrates include cellulosic substrates (coated paper,uncoated paper, wood), textiles, fibers, metal (metal foils), glass,ceramics, and plastics (tapes, films such as polyethylene films,polypropylene films and polyester films). Preferred substrates includepapers (SCK, OCR bond and glassine are examples), plastic films(polypropylene, polyethylene and polyesters are common examples) andmetal foils.

Preferred coated substrates are linerless or self-wound labels, adhesivetapes, label sheets and duplex forms which have labels integratedtherein.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding description, utilize the present invention toits fullest extent. The following preferred specific embodiments are,therefore, to be construed as merely illustrative, and not limitative ofthe remainder of the disclosure in any way whatsoever.

The entire disclosure of all applications, patents and publications,cited above or below, is hereby incorporated by reference.

EXPERIMENTAL EXAMPLES

Seven coating formulations were prepared with the epoxy-functionallinear polydimethylsiloxane polymer formulation UV POLY 230 availablefrom Bluestar Silicones® of New Brunswick N.J. This was a formulatedrelease coating, containing an iodonium borate salt cationicphotoinitiator at 2.5 wt %. The formulations had a viscosity in therange of 500-600 cps at 25° C. An unmodified formulation served as acontrol, while the other 6 formulations each included a differentreactive plasticizer.

The coating formulations were run on a conventional printing press toprint release layers for linerless labels at a coating-weight of 1.1±0.1g/cm². The release coatings were printed over the topcoated thermallyreactive coating of a direct thermal paper substrate (Kanzaki KL370NCR)and the pressure sensitive adhesive was applied to the reverse(uncoated) side of the web. The release coatings were cured uponexposure to 35-40 mJ/cm² UV radiation. Exposing each of the coatingformulations to UV light caused a rapid polymerization, curing each toform a tack-free, smear-free layer in less than 1 second directly on theroll stock. About 20 days after printing, rolls of linerless labels wereobtained after running the printed web through a slitter.

Of the seven formulations, five produced suitable linerless label stockwhich did not experience picking or blocking at the slitter, includingthe control UV230 without any reactive plasticizer. All experimentalformulations improved the flexibility of the silicone release layerbased on 1 mm Mandrel Bend testing observed under optical microscopy andall provided resilient layers that passed rub tests.

The five formulations which produced suitable label stock withoutpicking or blocking at the slitter had the following reactiveplasticizers in the amounts shown in Table 1:

1) none,

2) Pelmol P3D (Phoenix),

3) Pelmol DD (Phoenix),

4) UV9440E (Momentive) and

5) UV9440E (Momentive) and SIE4668.0 (Gelest).

TABLE 1 Additives Evaluated as Weight % Composition Phoenix GelestExample Commercial Pelmol Phoenix Momentive SIE Number UV230 P3D PelmolDD UV9440E 4668.0 1 100% Bluestar UV230 Control 3   95%   5% (95.0%)(5.01%) 4   95%   5% (95.0%) (5.02%) 2   95%   5% (95.0%) (5.00%) 594.5%   5%  0.5% (94.3%) (5.15%) (0.54%)

The values for weight % composition shown in the tables are targetvalues. The actual values for weight % composition on press are shown inparenthesis.

Three cases (30 rolls/case, for a total of 90 rolls; each roll was 270ft long, or 4.6 miles of receipts) of each linerless label stockformulation were sequentially printed in a thermal printer withoutperiodic cleaning of the thermal printhead and evaluated for printdefects, which are indicative of mechanical release coating damage.Defects were manifested by gaps in a specific region of the test receiptimage printed by the thermal printer. Such gaps are primarily attributedto the buildup of residue on the thermal printhead, which acts asthermal insulation, reducing the ability of the printhead to activatethe direct thermal coating. In addition to the number of gaps, thedefects were further characterized by the size (width) of the gaps inthe printed image. The data are based on a sampling rate of 1% of thesimulated receipts printed (120 of 12,000 receipts printed per case).The results are summarized in Table 2 below.

TABLE 2 Print Defects All Defects by Case - 30 Rolls Total Defects bySize - 90 rolls Sample Tested Case 1 Case 2 Case 3 1/32″- 1/16″1/16″-⅛″ >⅛″ Comments Example 1: 32 47 90 54 114 1 total defects perCase or size Standard UV230 0.267 0.392 0.750 0.150 0.317 0.003 %defects per Case or size CONTROL 266.7 391.7 750.0 150.0 316.7 2.8Defect rate/1000 per case or size Example 2: 49 67 65 78 101 2 totaldefects per Run or size 5% UV9440E 0.408 0.558 0.542 0.217 0.281 0.006 %defects per Run or size 408.3 558.3 541.7 216.7 280.6 5.6 Defectrate/1000 per case or size Example 3: 0 12 15 24 3 0 total defects perRun or size 5% Pelmol P3D 0.000 0.100 0.125 0.067 0.008 0.000 % defectsper Run or size 0.0 100.0 125.0 66.7 8.3 0.0 Defect rate/1000 per caseor size Example 4: 2 0 0 2 0 0 total defects per run or size 5% PelmolDD 0.017 0.000 0.000 0.006 0.000 0.000 % defects per run or size 16.70.0 0.0 5.6 0.0 0.0 Defect rate/1000 per case or size Example 5: 0 0 0 00 0 total defects per run or size Example 2 plus 0.000 0.000 0.000 0.0000.000 0.000 % defects per run or size 0.5% SIE 4668.8 0.0 0.0 0.0 0.00.0 0.0 Defect rate/1000 per case or size

The data in Table 2 shows significantly reduced print defects (lessdamage) by incorporation of 3 of the 4 reactive plasticizers that reactinto the polymer backbone of the release layer. The standard UV silicone(control) formulation had a total of 181 defects in 360 evaluatedreceipts, for a defect rate of 470/1000 receipts, whereas Example 3 hada total of 27 defects in 360 evaluated receipts, for a defect rate of75/1000 and Example 4 had a total of 2 defects in 360 evaluatedreceipts, for a defect rate of 6/1000. The importance of the combinedinteractions between the reactive plasticizer, the cure chemistry andthe substrate is demonstrated by comparing the results in Examples 2 and5. Importantly, while the reactive plasticizer in Example 2 showed noimprovement in the number of total defects, with a defect rate of503/1000 receipts, when a coupling agent was added to the sameformulation of reactive plasticizer and silicone, no defects occurred.

The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention and, withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

What is claimed is:
 1. A plasticized ultraviolet or electron beam(UV/EB) cationically cured coating comprised of polymers formed from: A.cationically polymerized monomers and/or oligomers, which are epoxymonomers, epoxy oligomers, oxetane monomers, oxetane oligomers, vinylether monomers, vinyl ether oligomers, or combinations thereof, and B.at least one reactive plasticizer which is permanently integrated withinsaid cured coating, which possesses one or more functional groups thatreact as chain transfer groups or chain terminating groups with thecationically polymerized monomers and/or oligomers, wherein the reactiveplasticizer is i. approved by the FDA as a direct food additive, ii.approved by the FDA as an indirect food additive in coatings andadhesives, iii. a cosmetic grade material iv. a medical grade materialand/or v. completely incorporated into the polymer backbone and isbiologically benign in that state.
 2. A plasticized ultraviolet orelectron beam (UV/EB) cationically cured coating as in claim 1 whereinthe reactive plasticizer comprises two or more functional groups capableof reacting as chain transfer groups or chain terminating groups withthe cationically polymerized monomer and/or oligomer.
 3. A plasticizedultraviolet or electron beam (UV/EB) cationically cured coating as inclaim 1 wherein the reactive plasticizer is a A. fatty acid, B. mono-,di-, triglyceride, or ester which contains reactive alcohol groups, C.diol or polyol, D. diacid or monoester thereof, E. low molecular weightpolyester (linear or branched) having one or more alcohol groups or oneor more carboxylic acid groups present as side chains or end groups, F.low molecular weight poly(meth)acrylate copolymer containing comonomerswith free OH and/or COOH groups G. anhydride, H. amide, or I. thiol. 4.A plasticized ultraviolet or electron beam (UV/EB) cationically curedcoating as in claim 3 wherein: A. the fatty acid is i. derived frombeechnut oil, candlenut oil, castor oil, chinawood (tung) oil, coconutoil, corn oil, cottonseed oil, fish (refined) oil, hempseed oil, linseedoil, oiticica oil, perilla oil, poppyseed oil, pumpkinseed oil,safflower oil, sesame oil, soybean oil, sunflower oil, walnut oil ortall oil; or ii. is capric acid, caprylic acid, lactic acid, lauricacid, linoleic acid, linolenic acid, myristic acid, oleic acid, palmiticacid propionic acid or stearic acid; B. the monoglyceride, diglyceride,triglyceride or ester, has free OH and/or COOH groups and is i. derivedfrom beechnut oil, candlenut oil, castor oil, chinawood (tung) oil,coconut oil, corn oil, cottonseed oil, fish (refined) oil, hempseed oil,linseed oil, oiticica oil, perilla oil, poppyseed oil, pumpkinseed oil,safflower oil, sesame oil, soybean oil, sunflower oil, walnut oil ortall oil; or ii. formed from multifunctional alcohols, which areglycerol, ethylene glycol or propylene glycol, triethylene glycol ortetraethylene glycol) and acids such as capric acid, caprylic acid,lactic acid, lauric acid, linoleic acid, linolenic acid, myristic acid,oleic acid, palmitic acid propionic acid or stearic acid; C. the diol orpolyol is butylene glycol, diethylene glycol, ethylene glycol, glycerol,mannitol, [alpha]-methyl glucoside, pentaerythritol, propylene glycol,diethylene glycol, triethylene glycol, tetraethylene glycol, dipropyleneglycol, tripropylene glycol and neopentyl glycol; sorbitol, trimethylolethane, trimethylol propane, tannic acid, glycerol and resveratrol; D.the diacid is adipic acid, aconitic acid, alginic acid,1,4-cyclohexanedicarboxylic acid, citric acid, dimerized fatty acidsderived from the oils identified above, fumaric acid, isophthalic acid,maleic acid, 2,6-naphthalenedicarboxylic acid, orthophthalic acid,sebacic acid, succinic acid, tartaric acid, terephthalic acid ortrimellitic acid and the monoester of the diacid is formed from butyleneglycol, ethylene glycol, pentaerythritol, polyethylene glycol,polypropylene glycol, propylene glycol, sorbitol, trimethylol ethane ortrimethylol propane; and E. the low molecular weight polyester ispolypropanediol dimer dilinoleate, dimer dilinoleyl dimer dilinoleate,polyglyceryl-3 behenate, polyglyceryl-6 behenate, polyglyceryl-6polyricinoleate, diisopropyl dimer dilinoleate or propanedioldicaprylate/caprate.
 5. A plasticized ultraviolet or electron beam(UV/EB) cationically cured coating as in claim 1 wherein the reactiveplasticizer is: propylene glycol, triethylene glycol, dipropyleneglycol, mannitol, sorbitol, p-tert-butyl phenyl salicylate, epoxidizedsoybean oil, glyceryl monooleate, monoisopropyl citrate, mono-, di-, andtristearyl citrate, triethyl citrate, 3-(2-Xenolyl)-1,2-epoxypropane,dihydroxy dichlorodiphenyl methane, glycerol or tributyl citrate.
 6. Aplasticized ultraviolet or electron beam (UV/EB) cationically curedcoating as in claim 1, wherein the reactive plasticizer is: A.polypropanediol dimer dilinoleate, B. dimer dilinoleyl dimerdilinoleate, C. polyglyceryl-6 behenate, D. polyglyceryl-6polyricinoleate, E. diisopropyl dimer dilinoleate or a combinationthereof.
 7. A plasticized ultraviolet or electron beam (UV/EB)cationically cured coating as in claim 1, wherein the reactiveplasticizer is a polydimethyl silicone polymer with diol end groupswhich completely incorporates in the polymer backbone and isbiologically benign in that state.
 8. A plasticized ultraviolet orelectron beam (UV/EB) cationically cured coating as in claim 1, whereinthe polymer additionally comprises at least one coupling agent havingthe formula R¹ _(n)—Si—OR² _((4-n)), where n is an integer from 1-3,preferably 2 and most preferably 1, R¹ contains a cationic-reactivegroup which is a cycloaliphatic epoxy, vinyl ether, or oxetane moiety,and R² is an optionally substituted C₁₋₆ hydrocarbon.
 9. A plasticizedultraviolet or electron beam (UV/EB) cationically cured coating as inclaim 8, wherein the one or more coupling agents are A.2-(3,4-epoxycyclohexyl)ethylmethyldiethoxy silane, B.2-(3,4-epoxycyclohexyl)ethyltriethoxy silane, C.2-(3,4-epoxycyclohexyl)ethyltrimethoxy silane, or D. 5,6-epoxyhexyltriethoxy silane.
 10. A plasticized ultraviolet or electron beam (UV/EB)cationically cured coating as in claim 9, wherein the reactiveplasticizer is a polydimethyl silicone polymer with diol end groupswhich completely incorporates in the polymer backbone and isbiologically benign in that state.
 11. A plasticized ultraviolet orelectron beam (UV/EB) cationically cured coating as in claim 1, appliedto a substrate by a conventional coating or printing process.
 12. Aplasticized ultraviolet or electron beam (UV/EB) cationically curedcoating as in claim 11, wherein the coating is a silicone release layercured by UV or EB radiation.
 13. A plasticized ultraviolet or electronbeam (UV/EB) cationically cured coating as in claim 11, wherein thecoating is a printed ink image cured by UV or EB radiation.
 14. Aplasticized ultraviolet or electron beam (UV/EB) cationically curedcoating as in claim 11, wherein the substrate is a linerless label ortape.
 15. A plasticized ultraviolet or electron beam (UV/EB)cationically cured coating as in claim 14, wherein the substrate is alinerless label or tape with print thereon from a thermal printer orother on-demand printer capable of variable print applications.
 16. AUV/EB cationically curable coating formulation which comprises A.cationically polymerizable monomers and/or oligomers selected from epoxymonomers, epoxy oligomers, oxetane monomers, oxetane oligomers, vinylether monomers, vinyl ether oligomers, and combinations thereof, and B.at least one reactive plasticizer, which possesses two or morefunctional groups that react as chain transfer groups or chainterminating groups with the cationically polymerized monomers and/oroligomers, wherein the reactive plasticizer is i. approved by the FDA asa direct food additive, ii. approved by the FDA as an indirect foodadditive in coatings and adhesives, iii. a cosmetic grade material, iv.a medical grade material and/or v. completely incorporated into thepolymer backbone and is biologically benign in that state. C. a cationicphotoinitiator activated by UV/EB radiation.
 17. A UV/EB cationicallycurable coating formulation of claim 16 wherein the reactive plasticizeris a A. fatty acid, B. mono-, di-, triglyceride, or ester which containsreactive alcohol groups, C. diol or polyol, D. diacid or monoesterthereof, E. low molecular weight polyester (linear or branched) havingone or more alcohol groups or one or more carboxylic acid groups presentas side chains or end groups, F. low molecular weight poly(meth)acrylatecopolymer containing comonomers with free OH and/or COOH groups G.anhydride, H. amide, or I. thiol.
 18. A UV/EB cationically curablecoating formulation of claim 17 wherein: A. the fatty acid is i. derivedfrom beechnut oil, candlenut oil, castor oil, chinawood (tung) oil,coconut oil, corn oil, cottonseed oil, fish (refined) oil, hempseed oil,linseed oil, oiticica oil, perilla oil, poppyseed oil, pumpkinseed oil,safflower oil, sesame oil, soybean oil, sunflower oil, walnut oil ortall oil; or ii. is capric acid, caprylic acid, lactic acid, lauricacid, linoleic acid, linolenic acid, myristic acid, oleic acid, palmiticacid propionic acid or stearic acid; B. the monoglyceride, diglyceride,triglyceride or ester, has free OH and/or COOH groups and is i. derivedfrom beechnut oil, candlenut oil, castor oil, chinawood (tung) oil,coconut oil, corn oil, cottonseed oil, fish (refined) oil, hempseed oil,linseed oil, oiticica oil, perilla oil, poppyseed oil, pumpkinseed oil,safflower oil, sesame oil, soybean oil, sunflower oil, walnut oil ortall oil; or ii. formed from multifunctional alcohols, which areglycerol, ethylene glycol or propylene glycol, triethylene glycol ortetraethylene glycol) and acids such as capric acid, caprylic acid,lactic acid, lauric acid, linoleic acid, linolenic acid, myristic acid,oleic acid, palmitic acid propionic acid or stearic acid; C. the diol orpolyol is butylene glycol, diethylene glycol, ethylene glycol, glycerol,mannitol, [alpha]-methyl glucoside, pentaerythritol, propylene glycol,diethylene glycol, triethylene glycol, tetraethylene glycol, dipropyleneglycol, tripropylene glycol and neopentyl glycol; sorbitol, trimethylolethane, trimethylol propane, tannic acid, glycerol and resveratrol; D.the diacid is adipic acid, aconitic acid, alginic acid,1,4-cyclohexanedicarboxylic acid, citric acid, dimerized fatty acidsderived from the oils identified above, fumaric acid, isophthalic acid,maleic acid, 2,6-naphthalenedicarboxylic acid, orthophthalic acid,sebacic acid, succinic acid, tartaric acid, terephthalic acid ortrimellitic acid and the monoester of the diacid is formed from butyleneglycol, ethylene glycol, pentaerythritol, polyethylene glycol,polypropylene glycol, propylene glycol, sorbitol, trimethylol ethane ortrimethylol propane; and E. the low molecular weight polyester ispolypropanediol dimer dilinoleate, dimer dilinoleyl dimer dilinoleate,polyglyceryl-3 behenate, polyglyceryl-6 behenate, polyglyceryl-6polyricinoleate, diisopropyl dimer dilinoleate or propanedioldicaprylate/caprate.
 19. A UV/EB cationically curable coatingformulation of claim 16 wherein the reactive plasticizer is A.polypropanediol dimer dilinoleate, B. dimer dilinoleyl dimerdilinoleate, C. polyglyceryl-6 behenate, D. polyglyceryl-6polyricinoleate, or E. diisopropyl dimer dilinoleate.
 20. A UV/EBcationically curable coating formulation of claim 16 wherein thereactive plasticizer is a polydimethyl silicone polymer with diol endgroups which completely incorporates in the polymer backbone and isbiologically benign in that state.
 21. A UV/EB cationically curablecoating formulation of claim 16, which additionally comprises at leastone coupling agent having the formula R¹ _(n)—Si—OR² _((4-n)), where nis an integer from 1-3, preferably 2 and most preferably 1, R¹ containsa cationic-reactive group which is a cycloaliphatic epoxy, vinyl ether,or oxetane moiety, and R² is an optionally substituted C₁₋₆ hydrocarbon.22. A UV/EB cationically curable coating formulation of claim 21 whereinthe one or more coupling agents are A.2-(3,4-epoxycyclohexyl)ethylmethyldiethoxy silane, B.2-(3,4-epoxycyclohexyl)ethyltriethoxy silane, C.2-(3,4-epoxycyclohexyl)ethyltrimethoxy silane, or D. 5,6-epoxyhexyltriethoxy silane.
 23. A UV/EB cationically curable coating formulationof claim 21 wherein the reactive plasticizer is a polydimethyl siliconepolymer with diol end groups which completely incorporates in thepolymer backbone and is biologically benign in that state.
 24. A UV/EBcationically curable coating formulation of claim 16 which is an ink.25. A UV/EB cationically curable coating formulation of claim 16 whichforms a release layer for an adhesive label.
 26. A UV/EB cationicallycurable coating formulation which comprises: A. cationicallypolymerizable monomers and/or oligomers selected from epoxy monomers,epoxy oligomers, oxetane monomers, oxetane oligomers, vinyl ethermonomers, vinyl ether oligomers, and/or combinations thereof, and B. atleast one coupling agent having the formula R¹ _(n)—Si—OR² _((4-n)),where n is an integer from 1-3, preferably 2 and most preferably 1, R¹contains a cationic-reactive group which is a cycloaliphatic epoxy,vinyl ether, or oxetane moiety, and R² is an optionally substituted C₁₋₆hydrocarbon, and C. a cationic photoinitiator activated by UV/EBradiation.
 27. A UV/EB cationically curable coating formulation of claim26 wherein the one or more coupling agents are A.2-(3,4-epoxycyclohexyl)ethylmethyldiethoxy silane, B.2-(3,4-epoxycyclohexyl)ethyltriethoxy silane, C.2-(3,4-epoxycyclohexyl)ethyltrimethoxy silane, or D. 5,6-epoxyhexyltriethoxy silane.
 28. An ultraviolet or electron beam (UV/EB)cationically cured coating comprising polymers formed from: A.cationically polymerized monomers and/or oligomers which are epoxymonomers, epoxy oligomers, oxetane monomers, oxetane oligomers, vinylether monomers, vinyl ether oligomers, and/or combinations thereof, andB. at least one coupling agent having the formula R¹ _(n)—Si—OR²_((4-n)), where n is an integer from 1-3, preferably 2 and mostpreferably 1, R¹ contains a cationic-reactive group which is acycloaliphatic epoxy, vinyl ether, or oxetane moiety, and R² is anoptionally substituted C₁₋₆ hydrocarbon.
 29. An ultraviolet or electronbeam (UV/EB) cationically cured coating of claim 28 wherein the one ormore coupling agents are A. 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane, B. 2-(3,4-epoxycyclohexyl)ethyltriethoxy silane, C.2-(3,4-epoxycyclohexyl)ethyltrimethoxy silane, or D. 5,6-epoxyhexyltriethoxy silane.